Clamp comprising two elements jammed on a rail



April 7, 1953 F. SURENDA 2,634,079

CLAMP COMPRISING TWO ELEMENTS JAMMED ON A RAIL Filed Sept. 20, 1950Patented Apr. 7, 1953 CLAMP COMPRISING TWO ELEMENTS JAMMED N ABAILFrank-J. Surenda, Freedom, Pa., assignor to Allis- ChalmersManufacturing Company, Milwaukee,

Wis.

Application September 20, 1950, Serial No. 185,740

3 Claims. 1,

This. invention relates to clamping devices and has particular.application to clamping objects against movement in. either of twodirections and where the space for providing the clamping structure isvery limited.v The clamping device claimed has application, for example,inside of casings for holding in position transformers or transformeraccessories which are spaced therefrom inside of the casing, such asterminal boards.

Various arrangements have been utilized to clamp or hold transformers orother apparatus in place inside of casings. It has been usual practiceto use clamping, members bolted to fixed structural parts of the casingand bolted to or acting against the transformer to hold the transformeror other apparatus in place. There are, however. several disadvantagesto the usual arrangements of clamping. devices. Their primarydisadvantages are the difiiculty of alignment of bolts or clamps withholes or notches in the fixed structure of the Casing and with the frameen closing the transformer, the necessity for the use of. both ordinaryand locking nuts, the inability to exactly adjust the position of theclamping device to compensate for the variances in size of apparatusbeing. clamped, and the inability of some clamping devices to firmlylock against movement of the apparatus in either of two directions.

It is an object of this invention to provide an improved clampingdevicewhich avoidsthe above mentioned disadvantages.

Other objects of this invention are to provide I a clamping device whichis a simple, compact,

inexpensive structure; is easily adjustable to any desired position; iseasily locked and unlocked in. position even in very confined spaces;and earn not be inadvertently moved from the locked position.

Objects and advantages other than those above set forth will be apparentin the following description when read in connection with theaccompanying drawing in which:

Fig. 1 is a side view of a transformer with its casing broken away toshow an embodiment of an invention;

Fig. 2 is an enlarged side view of the clamping device shown in Fig. lin the clamped position; Fig. 3 shows the clamping device partly insection and in the same position as in Fig. 2;

Fig. 4.is a section view taken on the line IV -IV of'Fig. 2.

The apparatus shown in Fig. 1 is provided with a casing Ill and a coverI I which is usually adapted to be attached to the flanged upper ed ofthe casing by bolts o clamps (not shown). A transformer coil and coreassembly [2 is located inside the casing and is provided with conductorcables l3 which are connected to bushingterminal members M of anysuitable type. The core of the transformer is clamped by means ofhorizontal angle irons l6 and vertical angle irons I! which are'held inplace by bolts. Guide members [8 and 19 may be attached to the angleirons at the top of the coil and core assembly by means of bolts 23, 24,respectively, and guide members 20, 2| are attached to the bottom of theassembly by bolts 25, 26. A pair of T-shaped resilient guide rails 21,28 are welded to the sidewalls of the casing at diametrically oppositevertically extending positions. The guide members I 8. I9, 20 and 2| aregrooved to cooperate with the guide rails so that the coil and coreassembly may be lowered into the casing with the guide members slidingupon the guide rails. The bolts 25, abut the bottom of the casing tosupport and prevent downward movement of the assembly from its positioninside the casing. The coil and core assembly is held in place againstupward movement in the casing by means of clamping devices 29 and 30.

The clamping device generally indicated at 29 includes two similarlyshaped resilient clamping elements 3!, 32 and a clamping bolt 33.Clamping' element 3| has at one end thereof a pair of arms 34 and 35which define a T-shaped slot. The dimensions of the slot are slightlylarger than the cross sectional dimension of the T-shaped guide rail soas to permit the clamping device to slide easily upon the guide rail.The opposite end of clamping element 3| has a tapped hole 36' to receivethe clamping bolt 33. The outline of element 3! shown in elevation inFig. 2 defines a first portion of about one-third the length of theelement of substantially constant width extending from the slotted endthereof to a point only a slight distance from the end of the slot. Fromthat point, defined as the fulcrum line 37, to the other end of theelement the upper edge of element 31 is cut away an amount equal toapproximately one-third the thickness of the first mentioned portion.

The other of the two clamping elements 32 has the same general shape aselement 3! and also has the same shape and size of T-shaped slot toslide easily upon. the guide rail. However, the end of element 32opposite to the slotted end, instead of being tapped, has a roundopening 38 there through of a size slightly larger than the size of theshank of bolt 33. The vertical cross sectional shape of the two clampingelements is the same.

As shown in Fig. 2, the top edge surface s: of element 32 is not flatbut is defined by two planar surfaces which intersect at an obtuse angleapproximately at the midpoint of the lengthwise dimension of theelement.

After the coil and core assembly has been lowered into the casing,elements 35 and 32 are slid down the rail 28 with their adjacent similarsurfaces 39 and 40, respectively, abutting against each other at thefulcrum line 3?. Clamping bolt 33 is inserted through opening 38 ofelement 32 and is screwed intotapped hole 36 of element 3! until thebottom of the bolt makes contact with guide member l8 and the head ofthe bolt makes contact with the fiat surface ll of element 32.

The bolt 33 is then screwed farther into element 3| causing elements 3!and 32 to rotate slightly about fulcrum line 3? until they engage theshank of the bolt and the headof the bolt is in contact with the flatupper surface ii of element 32. The resiliency of the cooperating twoelements acting about the fulcrum line and the resiliency of the guiderail cause the edge surface M to exert a force on the head of the boltpreventing the b0 t from accidentally working loose; l

A simple three piece clamping device is thus provided which veryeffectively locks itself against the rail preventing its movement ineither the upward or downward direction as viewed in Fig. 2 by theutilization of the coasting bolt and clamping elements which pivot abouta fulcrum line relatively close to the guide rail against which theyexert a force. The clamps thus prevent any upward movement of the coiland core assembly and hold the assembly down against the bottom of thecasing.

By the illustration of Fig. 3 it is particularly intended to moreclearly show the action of the clamping elements against the guide rail.When the clamping device is in its locked position there is a slightbending of the guide rail. The force Q5 which can be exerted through thejamming action of the clamp against the guide rail is greatly increasedover the force 45 the bolt exerts on the clamping element. Thecomparison of the length oftherelatively long lever arm 47 from the boltto the fulcrum linewith-thelength-of the relatively shorter lever arm 38from the fulcrum line to the remotest point of contact of the T'- shapedslot edges with the guide rail represents the great increase of forceexerted against the rail. Also the coaction of the two clamping elementstending to rotate about the fulcrum point provides two closely adjacentpoints of application of pressure against the guide rail to preventmovement of the clamping device in either the upward or downwarddirection. The coaction between the clamping elements and the bolt alsoprovides force applying means in contact with the core and coil assemblyand locking means for the bolt to prevent accidental or inadvertentloosening thereof.

.Although but one embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that changesand modifications may be made therein without departingfrom the spirit of the invention or from the scope of the appendedclaims.

It is claimed and desired to secure by Letters Patent:

l. A clamping device for restraining an object against movementcomprising the combination of a fixed guide rail and means including abolt, a first clamping element, and a second clamping element, each ofsaid elements having first and second ends and a contact surface, one ofsaid elements having its said contact surface formed intermediate itssaid ends to define a fulcrum line engageable with the said contactsurface of the other of said elements for relative pivoting of saidelements, said rail and said elements consisting of resilient material,the first end of each of said elements closely surrounding said rail,said elements abutting intermediate their ends at said contact surfaces,said bolt passing through an opening in the second end of said firstelement and threadedly received into the second end of saidsecondelement, said means being movable along said rail so that said bolt canmake contact with said object, said bolt being adjustable with respectto said elements to move said secondends of "said elements toward eachother with the head of said bolt engaging a thrust surface of said firstelement, thereby relatively pivoting said eleabout said fulcrum lineuntil said first ends of said elements jam against said rail, bolt thenabutting said object and when adjusted coacting through said elementswith said rail so that the resilience of said elements and of said railcauses a thrust on said object and prevents loosening of said means withrespect to said rail.

2. A clamping device for restraining an object from moving comprising afixed guide rail having a T-shaped cross section, force applying means,a "rst clamping element, and a second clamping element, said rail andsaid elements consisting of resilient material, each of saidelementshaving first and second ends and a contact surface, one of saidelements having its said contact surface formed intermediate its saidends to deiine a fulcrum line engaging the said contact surface of theother of said elements for relative pivoting of said elements, the firstend of each of said elements having a T-shaped slot slightly larger thanthe cross section of said rail, said rail re ceived in the slots of saidelement with said elements movable along said rail, said means connectedto the second ends of said elements and being engageable Withsaidlobjectrsaid means coasting with said elements and adjustable withrespect to said elements to force said second ends toward each other forrelatively pivotingsaid elements about said fulcrum line to thereby jamsaid first endson said rail, said means abutting said object and whenadjusted coacting through said elements with said rail so that theresilience of said elements and of said rail causes a thrust on saidobject.

against movement, said device comprising a fixed guide rail, anadjustable force applying means, and a pair of clamping elements havingfirst and second ends, said rail and said elements consis"- ing ofresilient material, said first ends of said elements substantiallyenclosing said rail, each of said elements having first and second endsand a contact surface, one of said elements having its said contactsurface formed to define a fulcrum line engageable with said contactsurface of the other of said elements, said force applying meansadjusted to act on said second ends to bring them toward each other,said elements in contact with each other along said fulcrum lineintermediate said force applying means and said rail, said force 3. Aclamping device for restraining an object FRANK J. SURENDA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Name Date Anderson July 21, 1931 Number

